2-238848298-G-A

Position:

• chr2-238848298-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_001271893.4(TWIST2):​c.83G>A​(p.Arg28His) variant causes a missense change. The variant allele was found at a frequency of 0.00000362 in 1,380,922 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000036 (0 hom.)
• Consequence: TWIST2 NM_001271893.4 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 6.37

Genes affected

TWIST2 (HGNC:20670): (twist family bHLH transcription factor 2) The protein encoded by this gene is a basic helix-loop-helix type transcription factor and shares similarity with Twist. This protein may inhibit osteoblast maturation and maintain cells in a preosteoblast phenotype during osteoblast development. This gene may be upregulated in certain cancers. Mutations in this gene cause focal facial dermal dysplasia 3, Setleis type. Two transcript variants encoding the same protein have been found. [provided by RefSeq, Apr 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Twist-related protein 2 (size 159) in uniprot entity TWST2_HUMAN there are 5 pathogenic changes around while only 1 benign (83%) in NM_001271893.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.23239774).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TWIST2	NM_001271893.4	c.83G>A	p.Arg28His	missense_variant	1/2	ENST00000612363.2
TWIST2	NM_057179.3	c.83G>A	p.Arg28His	missense_variant	1/2
TWIST2	XR_007069137.1	n.214G>A		non_coding_transcript_exon_variant	1/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TWIST2	ENST00000612363.2	c.83G>A	p.Arg28His	missense_variant	1/2	1	NM_001271893.4	P1
TWIST2	ENST00000448943.2	c.83G>A	p.Arg28His	missense_variant	1/2	1		P1
TWIST2	ENST00000710607.1	c.83G>A	p.Arg28His	missense_variant	1/2			P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000362 AC: 5 AN: 1380922 Hom.: 0 Cov.: 31 AF XY: 0.00000147 AC XY: 1 AN XY: 680950

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000464

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The TWIST2 p.Arg28His variant was not identified in the literature nor was it identified in dbSNP, ClinVar, Cosmic or LOVD 3.0. The variant was also not identified in the following control databases: the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project, the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. The p.Arg28 residue is conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.21	T;T
Eigen	Benign	0.12
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.91	D
M_CAP	Pathogenic	0.33	D
MetaRNN	Benign	0.23	T;T
MetaSVM	Uncertain	0.78	D
MutationAssessor	Benign	1.6	L;L
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	-2.3	N;.
REVEL	Uncertain	0.43
Sift	Benign	0.035	D;.
Sift4G	Benign	0.073	T;T
Polyphen		0.0090	B;B
Vest4		0.091
MutPred		0.32		Loss of MoRF binding (P = 0.0519);Loss of MoRF binding (P = 0.0519);
MVP		1.0
MPC		1.9
ClinPred		0.91	D
GERP RS		4.9
Varity_R		0.19
gMVP		0.73

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-239756939;